Step 1: Analyze the integrals.
The integral involves the difference of two functions, \( e^{\sin x} \) and \( e^{\cos x} \). Both functions are periodic with a period of \( \pi \), and over the interval \( \left[ 0, \frac{\pi}{2} \right] \), their values cancel out.
Step 2: Conclusion.
The integral evaluates to 0. Hence, the correct answer is (B) 0.